add grpc metadata util

pkg/grpcx/metadata.go

@@ -0,0 +1,46 @@
+package grpcx
+
+import (
+	"context"
+	"strings"
+
+	"google.golang.org/grpc/metadata"
+)
+
+// GetIncomingMetaData get grpc incoming metadata from grpc context
+func GetIncomingMetaData(ctx context.Context) (metadata.MD, bool) {
+	return metadata.FromIncomingContext(ctx)
+}
+
+// GetMetaDataFirst get metadata first value by key
+func GetMetaDataFirst(md metadata.MD, key string) string {
+	if md == nil {
+		return ""
+	}
+
+	if v := md.Get(key); len(v) > 0 {
+		return v[0]
+	}
+	return ""
+}
+
+// GetUserAgent get user agent from grpc context
+func GetUserAgent(ctx context.Context) string {
+	md, _ := GetIncomingMetaData(ctx)
+	return GetMetaDataFirst(md, "user-agent")
+}
+
+// GetRealIP get user ip from grpc context
+func GetRealIP(ctx context.Context) string {
+	md, _ := GetIncomingMetaData(ctx)
+	xff := GetMetaDataFirst(md, "x-forwarded-for")
+	if i := strings.IndexAny(xff, ","); i > 0 {
+		return strings.TrimSpace(xff[:i])
+	}
+
+	if xrip := GetMetaDataFirst(md, "x-real-ip"); len(xrip) > 0 {
+		return xrip
+	}
+
+	return ""
+}